Toxicologia Ambiental e Analítica

This review summarizes recent literature related to analytical method development, assessment, and removal of emerging contaminants in natural water resources and drinking water. This review mainly focuses on the following four groups of chemical contaminants: pharmaceuticals and personal care products (PPCPs); major disinfection byproducts, cyanotoxins, and pesticides and herbicides. Because of the large volume publications on various emerging environmental contaminants, articles relating to specific water treatment, health risk assessments and ecological impact are not included in this review. In addition, literature pertinent to emerging contaminants in air and other environments are also not covered in this review.

Aggregation of engineered nanoparticles (NPs) plays a crucial role in their environmental transport, fate,bioavailability and biological effects. This study investigated the temperature effect on the aggregation kinetics of CeO2 NPs in KCl and CaCl2 solutions using time-resolved dynamic light scattering. The results show that in KCl and CaCl2, the aggregation rate became faster as the temperature increased. The critical coagulation concentration (CCC) of CeO2 NPs went down from approximately 100 to 10 mM in KCl and from approximately 10 to 2 mM in CaCl2 solutions when the temperature increased from 4 to 37°C. The observations were analyzed in the framework of extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory in order to find out the mechanisms underlying the temperature effect. Moreover, a theoretical model developed on the basis of EDLVO theory and von Smoluchowski’s population balance equation was used to predict the aggregation kinetics of CeO2 NPs under different temperature. The model predictions agreed well with experimental data, suggesting that the model could be employed to predict the size change of NPs in solution. Overall, this work provides insights into NP aggregation using experimental and modeling approaches, and allows people to better understand and theoretically predict the environmental behavior and risk of NPs.

Dendroaspis polylepis polylepis is the most toxic snake commonly known as black mamba, the black mamba venom contains Dendrotoxin-K which is highly specific and virulently toxic protein. Antigenic peptides of Dendrotoxin toxic protein are most suitable for peptide vaccine development because with single epitope, the immune response can be generated in large population. Analysis shows MHC class II binding peptides of antigenic protein from Dendroaspis polylepis polylepis DTX-K are important determinant for protection against several venom toxins. In this assay we predicted the binding affinity of Dendroaspis polylepis polylepis DTX-K protein having 79 amino acids, which shows71nonamers. In this analysis, we found the High affinity TAP Transporter peptide regions as, 37-KRKIPSFYY(score-9.550), 45-YKWKAKQCL (Score-8.581) 36-CKRKIPSFY (Score-7.685), 24-AKYCKLPLR (Score-7.669), 42-SFYYKWKAK (Score-6.859), 31-LRIGPCKRK (Score-6.848) 65-NRFKTIEEC (Score-6.698), 25-KYCKLPLRI (Score-6.632), 49-AKQCLPFDY (Score-6.576), 66-RFKTIEECR (Score-6.464), 47-WKAKQCLPF (Score-6.197), 23-AAKYCKLPL (Score-6.166). We also found the SVM based MHCII-IAb peptide regions, 61-GGNANRFKT, 12-TLWAELTPV, 41-PSFYYKWKA, 25-KYCKLPLRI (optimal score is 0.946); MHCII-IAd peptide regions, 2-GHLLLLLGL, 57-SGCGGNAN, 3-HLLLLLGLL, 1-SGHLLLLLG (optimal score is 0.488); MHCII-IAg7 peptide regions 60-CGGNANRFK, 21-SGAAKYCKL, 61-GGNANRFKT, 20-VSGAAKYCK (optimal score is 1.468); and MHCII-RT1.B peptide regions 46-KWKAKQCLP, 24-AKYCKLPLR, 10-LLTLWAELT, 45-YKWKAKQCL (optimal score is 0.569) which represented predicted binders from dendrotoxin. The method integrates prediction of peptide MHC class I binding; proteasomal C terminal cleavage and TAP transport efficiency of the Dendroaspis polylepis polylepis DTX-K. Thus a small fragment of antigen can induce immune response against whole antigen. This theme is implemented in designing subunit and synthetic peptide vaccines.

Phytoremediation is an emerging technology for cleaning up contaminated sites, which is cost effective, and has aesthetic advantages and long term applicability. The report suggests about the mobility, bioavaliability and plant response to the presence of soil heavy metals. A greenhouse experiment was conducted to determine the phytotoxic effect of heavy metals such as Ni and Pb on the growth of Georgina wild. The selected metals were dosed at various concentration ranging from 0.5, 1.0, 1.5, 2.0 mg/kg for nickel and 5.0, 10, 15, 20 mg/kg for lead separately in soil. The results revealed that as the concentration of heavy metal in soil increases, the overall length of plant decreases with respect to control.

The present study was conducted to investigate the protective effects of a synthetic antioxidant “acetyl gallate derivative” (SAC) against hepatic oxidative stress and brain DNA damage induced by dimethoate (DM) in male rats. DM was orally administrated to the rats at a dose of 38.7 mg kg-1 b.wt. (1/10 LD50), for 28 consecutive days. Additional DM groups received either SAC or vitamin C (VC) at a dose of 200 mg kg-1 b.wt. 30 min before DM administration. Compared to the control, DM induced a statistical reduction in body weight gain, while induced a statistical increase in absolute and relative liver weights. Oral administration of DM significantly caused increases in hepatic lipid peroxidation (LPO) and activities of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD) and glutathione-s-transferease (GST), while caused decreases in glutathione content (GSH) and serum cholinesterase(ChE) activity. Administration of SAC attenuates LPO, GSH content and antioxidant enzymes system. The severity of brain DNA damage monitored by damage index (DI) and damage frequency % (DF) induced by DM was mitigated after administration of SAC. In conclusion, supplementation of SAC is more reliable than VC in attenuating relative liver weight, SOD, GST, and brain DNA damage.

Wastewater containing heavy metal ions is considered as the serious environmental problem in human society. Adsorption as the widely used method plays an important role in wastewater treatment, which is based on the physical interaction between metal ions and sorbents. With the development of nanotechnology, nanomaterials are used as the sorbents in wastewater treatment; several researches have proved that nanomaterials are the effective sorbents for the removal of heavy metal ions from wastewater due to their unique structure properties. Three kinds of nanomaterials are presented in this paper, including nanocarbon materials, nanometal particles, and polymer-supported nanoparticles.For heavy metal ions, all these nanomaterials show high selectivities and adsorption capacities. Besides, the adsorption isotherm model and adsorption kinetics are introduced briefly to understand the adsorption procedure.

In this study, CuS micro-flake with average sizes of about 5–10 μm grows on 3D copper foam was synthesized by solvothermal method. This material was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Besides, this CuS material was used to degrade methylene blue (MB) dye, water as catalyst and the effect of reaction temperature was also discussed.

Pharmaceuticals and personal care products (PPCPs) are considered as the emerging environmental problem in the recent years. The elimination of PPCPs during water treatment are investigated at lab through different advanced oxidation processes (AOPs), which are the technologies based on the intermediacy of hydroxyl and other radicals to oxidize pollutants. Catalytic ozonation is proved as an effective technology for the removal of organics from wastewater. The paper presents a short review about the introduction of the ozonation catalysts and the reaction mechanism of the catalytic ozonation. The main aim is to provide a new and effective method in the removal of PPCPs in the aqueous solution.

Significant needs and efforts have been made in the development of novel hydrogels for early detecting and effectively removing heavy metal ions from environments. In this review, three types of hydrogels used for removal of heavy metal ions and associated ion capture-release mechanisms are discussed. Well-defined three-dimensional porous structures, coupled with highly hydrated and versatile chemical groups, are the keys to developing effective hydrogels for removal of toxic heavy ions. Biomolecule-conjugated hydrogels and stimuli-responsive hydrogels are the promising next generation materials for detection and removal of toxic heavy metal ions due to their selectively binding metal ions in a controlled manner.